Awesome one-day run from the South Rim to the North Rim (via Bright Angel and N Kaibob) and back (via N and S Kaibob). Next time I'll descend the S Kaibob and ascend the Bright Angel as the S Kaibob is a grueling steep nasty climb after a full day out. In total (not counting the 3 mile walk back to Mather Campground (no shuttle service after 7:30pm)) was 46 miles, 11,400' of gain, 17 hours. The North Kaibob Trail was by far my favorite stretch... very beautiful.